First, the carbon nanotubes - tiny tubes of tightly rolled carbon that are 400 hundred times smaller than the diameter of a strand of hair - help absorb some of the light.

The nanotubes are standing on end, much like a patch of grass and light is trapped in the tiny gaps between the "blades".

The researchers have also made the surface of this carbon nanotube carpet irregular and rough to cut down on reflectivity.

"Such a nanotube array not only reflects light weakly, but also absorbs light strongly," says Shawn-Yu Lin, a professor of physics at Rensselaer, who helped make the substance.

The researchers have tested the material on visible light only. Now they want to see how it fares against infrared and ultraviolet light, and other wavelengths such as radiation used in communications systems.

"If you could make materials that would block these radiations, it could have serious applications for stealth and defence," Ajayan says.

The Indian-born Ajayan holds the 2006 Guinness World Record as co-inventor of the smallest brush in the world.